Notocupes rostratus Ponomarenko, 1969

STRELNIKOVA, OLESYA D. & YAN, EVGENY V., 2023, Redescriptions of the Triassic Notocupes beetles (Archostemata: Ommatidae) from Kyrgyzstan and South Kazakhstan, Palaeoentomology 6 (2), pp. 174-190 : 184-186

Notocupes rostratus Ponomarenko, 1969

( Figs 8 , 9 )

Notocupes rostratus Ponomarenko, 1969: 90 .

Material. Holotype and paratype PIN 2240 /66, part and counterpart of almost complete body .

Holotype. PIN 2555 /1664, part and counterpart of almost complete body, Dzhayloucho locality, Kyrgyzstan, Osh Province, Batken region, Middle-Upper Triassic , Madygen Formation.

Diagnosis. Antennae not reaching base of pronotum. Antennomeres 4–8 equal in length. Head strongly elongate in front of eyes. Elytron with up to 32 cells in one row. Abdominal apex acute.

Description. Cuticular tubercles rounded, uniformly covering body, tubercle diameter 0.03–0.04 mm, space between adjacent tubercles 0.03 mm, less than size of one tubercle; density of cuticular sculpture 350 tubercles per mm².

Head elongate, especially in front of eyes, head (including length of mandibles) to body length ratio 5.8–6. Head length in front of eyes 1.5× eye length, head length behind eyes little shorter than eye length. Eyes large, protruding laterally, eye longitudinal diameter 0.4–0.5 mm, transverse diameter 0.2 mm. Head width (excluding eyes) to eye width ratio 3.7–4.6. Head protuberances more or less indistinct, outlines of P1 and P2 visible. Clypeolabrum rounded. Mandibles more or less straight, with only apices gradually curved inwards, with 3 apical denticles. Antennae attached laterad to mandibular bases, their bases obscured by supraantennal protuberance.

Scapus enlarged, 2× as wide as other antennomeres, 1.7×as long as pedicellus, 1.3×as long as 3 rd, antennomeres 4–8 subequal in size and shape, shorter the three basal ones. Аntennae clearly not reaching base of pronotum.

Pronotum transverse, with maximum width at midlength, narrowing anteriorly and posteriorly; posterior angles rounded; lateral margin not serrated. Anterior margin not concave; anterior angles protruding only slightly. Pronotal disc with pair of oval medial elevations and with furrow between them. Notopleural suture slightly oblique.

Elytron maximum wide at midlength. Elytral cells oval, of same size and shape in all fields. Field I with single row of cells, others with double rows; cells in field III 32, field IV 30–32 cells, field V have 24–25, field VI 30. Maximum number of cells in row to elytral length ratio 4.4. Maculae present, about 6–7 per cell, but exact number unknown due to imperfect preservation. Cells occupying more than half distance between veins and almost reach borders of veins. Elytral length to width ratio 3.3. Elytra not longer than abdomen. Veins 2 and 3 run along elytron, gradually curving inwards, reaching elytral apex. Veins 4 and 5 merging together three cells before elytral apex. Еpipleuron gradually narrowing throughout its length. Epipleuron width ratio at elytron base and apex 5. Elytron maximum to epipleuron maximum width ratio 4.5. Elytral apex rounded and not protruding posteriorly.

Metaventrite as wide as long; posterior margin width 3.2× anterior margin. Рaracoxal suture approximate to but not merging with posterior margin of metaventrite.

Abdomen with weakly defined relief, anterior margins of sternites II–IV with transverse impression, apical sternite with medial longitudinal furrow ( Fig. 8B, C ). Sternites length ratio 2–2.4:1:1:1:2–2.5. Abdominal apex is strongly acute, without median fossa.

Procoxae adjacent, weakly transverse, coxal cavities open posteriorly ( Fig. 9D , cx.cv). Profemora widest at midlength. Mesocoxae adjacent, weakly transverse.

Measurements (in mm): holotype PIN 2555/1664: body length 10.9, width 3.8, elytron length 6.3–7.3, width 1.9; paratype PIN 2240/66: body length 10.5, elytron length 7.3–7.7.

Remarks. Differs from all other species in having peculiar paired, oval impressions on posterior margins of abdominal sternites and abdominal apex without median fossa. Similar to N. laticella and N. tenuis in antennal bases covered by supraantennal protuberance. Similar to N. laticella , N. tenuis and N. oxypygus in having dense, uniform cuticular tubercles. Similar to N. oxypygus in strongly acute abdominal apex.

The elytral length of the holotype has a range of values, since the elytron was preserved at different angles with respect to the direction of postmortem deformation of the hosting rock, when one elytron of the same specimen was stretched more than the other.

Figures

FIGURE 8. Notocupes rostratus, holotype (PIN, 2555/1664). A, Mirrored photo of dry counterpart. B, Photo of dry part. C, Interpretative line drawing of part. D, General scheme of elytra. Abbreviations: fem, femur.

FIGURE 9. Notocupes rostratus, paratype (PIN, 2240/66). A, Mirrored photo of dry counterpart. B, Photo of dry part. C, Tubercles on the body. D, Interpretative line drawing of part. Abbreviations: cx.cv, coxal cavities.